In the grandstand Gerald Davies shed tears of joy and grief, while down on the pitch the young men decked in red celebrated Wales's third Grand Slam in eight seasons. Mervyn Davies would have been more than proud. Like all his countryman he would have been euphoric. This was a triumph cast in the image of Merv The Swerve, the nation's most iconic captain who passed away two days before. Wales dug deep when they had to, swerved when they had to and from the morass of French negativity they picked out their immortality. It says so much about this team's achievement that the talk wasn't just of revenge for the one-point loss to the same opponents in the World Cup semi-final four months ago. There were simply too many positive emotions to allow bitterness to dominate the aftermath.

Just like in Auckland, however, Wales lost Sam Warburton in the first half; not, this time, to a red card, but to a shoulder injury. No matter. Sam, their captain, used one hand to pick up the trophy which confirms Wales as the union kings of the northern hemisphere. Behind him the trio of Ryan Jones, Gethin Jenkins and Adam Jones led the victory dance. They had joined Gareth Edwards, JPR Williams and Gerald Davies himself, in gaining hat-tricks of Grand Slams. Clubs don't get much more exclusive than that. Yes, it was impossible not to think back to the Seventies; to the last time a Welsh team won three in eight from 1971-78; to the days of Mervyn and all those legends.

Dan Lydiate is priceless, there's no doubting that claim. He summed up his own crazily-committed performance in one short sentence uttered with mangled nasal tones which implied a broken nose had been sustained. "Well, you've got to throw your body on the line to win a Grand Slam, haven't you?" said the blindside. Lydiate's flanking masterclass encapsulated a Welsh display of composure, control and clinical competence.

France came to the capital unashamedly casting themselves in the role of ultimate party-poopers. They prayed for it to rain on the Welsh parade, insisting the roof stay open. The heavens duly consented with an hour to kick-off and any chance of an open attractive encounter disappeared.

Wales coped with the expectation of being favourites against a country they had lost to 10 times in the previous 12 encounters. And Wales played the conditions. Balls popped out of hands, players went slipping and chaos threatened to reign. If Imanol Harinordoquy has ever dropped the ball more in a game then he must have been wearing boxing gloves. To France's credit, their defence refused to buckle. There was only one real line break in the entire game and that was when Alex Cuthbert scored the only try. What a finish it was by the Gloucester-born winger. The turnover was created by a Lydiate spine-cruncher – this one on Thierry Dusautoir – and quick, as a flash, the ball was worked to Cuthbert. Two steps off the right foot, the first bamboozling Julien Bonnaire, the second leaving Clement Poitrenaud clutching oxygen, and the 21-year-old was under the posts.

A nervous scrappy opening had featured a France penalty from Dmitri Yachvili. But the breakthrough after 21 minutes seemed to suck out the tension from the Millennium. Wales twice hit the post with penalties in the first half, although Leigh Halfpenny's three points allowed them to run in 10-3. France had been witless in attack, with their barrel-chested fly-half Lionel Beauxis offering nothing but the punt. Their backline was assembled to resist; nothing much more.

They did have their chances, however. After seeing Ryan Jones run out instead of Warburton – the No 7 put of action by William Servat clearing out at a ruck – Beauxis reduced the deficit to four. But a few minutes later he showed the limitation of his limitation by instantly going for a drop-goal just as France were setting up camp on the 22. Beauxis missed. Halfpenny didn't. The last time the full-back was faced with a penalty from halfway against France, the World Cup final beckoned. This time he wasn't short, the ball soaring through the uprights. It handed Wales a little breathing space, although with 15 minutes remaining the French rumbled close to the line. But that man Lydiate forced the penalty and the Welsh to punch the air.

Yachvili reduced the gap to four again with six minutes left, but this was when the home side stood most tall. Showing a maturity which belies their years, they bashed their way upfield. Halfpenny landed another penalty and then Wales returned into the French quarter. In those final minutes, France weren't given so much as a squeak of a game-tying try and conversion. Instead they were left to grapple in frustration as the crowd began the most joyous of countdowns. "This one's for Merv," said Lydiate. The Welsh were set to repeat that statement all night.